added, at the beginning of the oo rewrite

Alien/Package.pm

@@ -0,0 +1,228 @@
+#!/usr/bin/perl -w
+
+=head1 NAME
+
+Alien::Package - an object that represents a package
+
+=cut
+
+package Alien::Package;
+use strict;
+use vars qw($AUTOLOAD);
+
+=head1 DESCRIPTION
+
+This is a perl object class that represents a package in an internal format
+usable by alien. The package may be a deb, a rpm, a tgz, or a slp package,
+etc. Objects in this class hold various fields of metadata from the actual
+packages they represent, as well as some fields pointing to the actual
+contents of the package. They can also examine an actual package on disk,
+and populate those fields. And they can build the actual package using the
+data stored in the fields.
+
+A typical use of this object class will be to instantiate an object from
+a class derived from this one, such as Alien::Package::Rpm Feed the object
+a rpm file, thus populating all of its fields. Then rebless the object into
+the destination class, such as Alien::Package::Deb. Finally, ask the object
+to build a package, and the package has been converted.
+
+=head1 FIELDS
+
+=over 4
+
+=item name
+
+The package's name.
+
+=item version
+
+The package's upstream version.
+
+=item release
+
+The package's distribution specific release number.
+
+=item arch
+
+The package's architecture, in the format used by Debian.
+
+=item maintainer
+
+The package's maintainer.
+
+=item depends
+
+The package's dependancies.
+
+=item group
+
+The section the package is in.
+
+=item summary
+
+A one line description of the package.
+
+=item description
+
+A longer description of the package. May contain multiple paragraphs.
+
+=item copyright
+
+A short statement of copyright.
+
+=item distribution
+
+What distribution family the package originated from.
+
+=item conffiles
+
+A reference to a list of all the conffiles in the package.
+
+=item files
+
+A reference to a list of all the files in the package.
+
+=item postinst
+
+The postinst script of the package.
+
+=item postrm
+
+The postrm script of the package.
+
+=item preinst
+
+The preinst script of the package.
+
+=item prerm
+
+The prerm script of the package.
+
+=item unpacked_tree
+
+Points to a directory where the package has been unpacked.
+
+=item filename
+
+The filename of the package the object represents.
+
+=back
+
+=head1 METHODS
+
+=over 4
+
+=item new
+
+Returns a new object of this class. Optionally, you can pass in named
+parameters that specify the values of any fields in the class.
+
+=cut
+
+sub new {
+	my $proto = shift;
+	my $class = ref($proto) || $proto;
+	my $this=bless ({@_}, $class);
+	$this->init;
+	return $this;
+}
+
+=item init
+
+This is called by new(). It's a handy place to set fields, etc, without
+having to write your own new() method.
+
+=cut
+
+sub init {}
+
+=item read_file
+
+This method looks at the actual package file the package represents, and
+populates all the fields it can from that package file. The filename field
+should already be set before this method is called.
+
+(This is just a stub; child classes should override it to actually do
+something.)
+
+=cut
+
+sub read_file {
+	my $this=shift;
+	my $file=$this->filename;
+
+	if (! -e $file) {
+		die "`$file' does not exist; cannot read.";
+	}
+}
+
+=item unpack
+
+This method unpacks the package into a temporary directory. It sets
+unpacked_tree to point to that directory.
+
+(This is just a stub method that makes a directory below the current
+working directory, and sets unpacked_tree to point to it. It should be
+overridden by child classes to actually unpack the package as well.)
+
+=cut
+
+sub unpack {
+	my $this=shift;
+	
+	my $workdir = $this->name."-".$this->version;
+	mkdir $workdir, 0755 ||
+		die "unable to mkdir $workdir: $!";
+	$this->unpacked_tree($workdir);
+}
+
+=item DESTROY
+
+When an object is destroyed, it cleans some stuff up. In particular, if the
+package was unpacked, it is time now to wipe out the temporary directory.
+
+=cut
+
+sub DESTROY {
+	my $this=shift;
+
+	return if (defined $this->unpacked_tree || $this->unpacked_tree eq '');
+	# This should never happen, but it pays to check.
+	if ($this->unpacked_tree eq '/') {
+		die "alien internal error: unpacked_tree is set to `/'. Please file a bug report!";
+	}
+	system 'rm', '-rf', $this->unpacked_tree &&
+		die "unable to delete temporary directory `".$this->unpacked_tree."`: $!";
+	$this->unpacked_tree('');	
+}
+
+=item AUTOLOAD
+
+Handles all fields, by creating accessor methods for them the first time
+they are accessed.
+
+=cut
+
+sub AUTOLOAD {
+	my $field;
+	($field = $AUTOLOAD) =~ s/.*://;
+
+	no strict 'refs';
+	*$AUTOLOAD = sub {
+		my $this=shift;
+
+		return $this->{$field} unless @_;
+		return $this->{$field}=shift;
+	};
+	goto &$AUTOLOAD;
+}
+
+=back
+
+=head1 AUTHOR
+
+Joey Hess <joey@kitenet.net>
+
+=cut
+
+1